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Cannabis Legalization & Opioid Therapy Compliance

Am J Med; ePub 2018 Nov 10; Lo, et al

In patients treated with opioid therapy for chronic pain, the legalization of recreational cannabis does not affect compliance rate, a new study found. Researchers conducted a retrospective cohort study on results from a “high-risk” urine drug testing panel. Results from 1 year before and 1 year after initiation of recreational cannabis legislation were analyzed. The testing panel included qualitative assays for cannabinoids and 9 other common drugs of abuse, in addition to a quantitative LC-MS/MS assay for 23 different opioids and metabolites. They found:

  • In the pre-legalization period, 1,776 panels were performed; 1,648 panels were performed post-legalization.
  • An increase in the rate of positive cannabinoid results was observed after legalization of recreational cannabis.
  • However, the overall compliance rate was consistent.


Lo SY, Winston-McPherson GN, Starosta AJ, et al. Cannabis legalization does not influence patient compliance with opioid therapy. [Published online ahead of print November 10, 2018]. Am J Med. doi:10.1016/j.amjmed.2018.11.002.